Sr3Bi(PO4)3:Eu2+, Mn2+: Single-phase and color-tunable phosphors for white-light LEDs

• The successful co-doping of Eu2+ and Mn2+ ions in Sr3Bi(PO4)3.
• The tunable emission color of Sr3Bi(PO4)3:Eu2+, Mn2+ phosphors.
• Efficient energy transfer from Eu2+ to Mn2+ ions in Sr3Bi(PO4)3.
• Good thermostability of synthesized Sr3Bi(PO4)3:Eu2+, Mn2+ phosphors.

Sr3Bi(PO4)3:Eu2+, Sr3Bi(PO4)3:Mn2+, and Sr3Bi(PO4)3:Eu2+, Mn2+ phosphors were synthesized by solid state reaction. The structure and luminescent characteristics were investigated by X-ray powder diffraction and fluorescent spectrophotometer. All samples have the structural type of eulytine. The excitation and emission spectra of Sr3Bi(PO4)3:0.01Eu2+ sample show characteristic bands of Eu2+ ions. Also, the excitation and emission spectra of Sr3Bi(PO4)3:0.06Mn2+ sample show characteristic bands of Mn2+ ions. The emission color of Sr3Bi(PO4)3:Eu2+, Mn2+ sample could be tuned through tuning the co-dopant concentration of Mn2+ ions. The decay times for the Eu2+ ions decrease with the increase of Mn2+ dopant concentration, but the energy transfer efficiency increases with the increase of Mn2+ dopant concentration. On the basis of the luminescent spectra and fluorescence decay curves, we confirm that the energy transfer process from the Eu2+ to Mn2+ ions takes place in the co-doped Sr3Bi(PO4)3 phosphor. Sr3Bi(PO4)3:Eu2+, Mn2+ sample shows the good thermostability. The emission intensity of the sample at 400 K is about 60% of the value at 300 K. These results show Sr3Bi(PO4)3:Eu2+, Mn2+ phosphors could be anticipated for UV-pumped white-light-emitting diodes.